DE1942388B - Process for the preparation of unsaturated C deep 2 to C deep 4 acetic acid esters - Google Patents

Description

In British patent specification 975 683 there is a ver ao The redox system is suitably a metal salt, drive for the production of carboxylic acid esters unge like a copper salt, z. B. copper halide, such as saturated copper monohydric alcohols by reaction of a chloride or a copper carboxylate, such as copper olefin, Containing a maximum of four carbon atoms, altanoate with 1 to 6 carbon atoms, ζ. Β. Copperin Presence of a palladium salt, a carboxylate, acetate. The concentration of the redox system is before that is ionized under the reaction conditions, as preferably up to 2.0 molar, in particular 0.05 to and a redox system in a carboxylic acid!, Omolar.

wrote, whereby the redox system by means of molecular The palladium salt can be a halide, such as palladium

Oxygen is regenerated. The method is to be dium (II) chloride or a carboxylate. Suitable characterized in that the olefin partial pressure Carboxylates are alkanoates with 2 to 6 carbon size than atmospheric pressure. 30 atoms, ζ. B. Palladium (II) acetate. The concentration

In this method, oxygen and ethylene of the palladium salt can range from 10 - are routed to together in the carboxylic acid solution l.Omolar, preferably 10 ~ ⁴ - - * to 10- ² are molar, and the unsaturated ester is prepared therefrom in the method can be used at a temperature in

The gas stream leaving the solution can be removed, ranging from 80 to 200 ^° C., preferably 100 to 180 ° C., however, the reaction rate being carried out relatively.

is low. Generally there is water in the reaction solution

A process was found for the production of saturated C ₂ to C ₄ acetic acid esters by reaction, which is not due to the reoxidation of the redox system. The water concentration can be in the range from 5 to ethylene, propylene and butylene with oxygen and 15 percent by weight.

Acetic acid in the presence of a redox system, a 4 ° Under certain circumstances it is beneficial to have a Palladium salt and acetate ions as well as a given supply of halide ions to be provided in the solution, if halide ions dissolved in the acetic acid, this can be achieved by alkali metal or alkaline earth metal halide, e.g. B. found in the liquid phase at a higher temperature, the lithium chloride happened. The halide concentrations thereby is characterized in that the mixture can be tration up to l.OmoIar, preferably 0.05 to Olefin and oxygen at a rate of 45.5 molar.

at least 4000 liters / liter of reaction solution / hour, The products of the process, such as vinyl acetate, are

preferably in the range of 4,000 to 8,000 liters / liter, valuable as polymerizable monomers.
Reaction solution / hour, introduced into the reaction solution. example 1

The method according to the invention is characterized 50

mainly due to increased reaction speed- A gas mixture of 4 volume percent oxygen and

speed and thus through increased yield of products, 96 percent by volume of ethylene was achieved at 4250 liters per liter that is achieved per unit of time. In addition, the reaction mixture can be passed into a solution per hour, consisting of the ratio of unsaturated ester to by-products
can be increased, for example, when ethylene reaches 55 _. _ ^ r _n ,

is olefin used in the reaction, the ratio tissigsaure odu mi

increased from vinyl acetate to acetaldehyde. Lithium acetate 0.8 mo ar

Ethylene is the most important olefin used in Lithramchlond 0,2mo ar

in the process. Propylene is also a common copper (II) acetate 0.2 molar

bare reaction component in the process, where «So The temperature was 122 ° C and the pressure

the product is allyl acetate. 27 atmospheres. Palladium (II) chloride was used at

The partial pressure of the olefin used is before a rate of O.OOlmolar in the first

preferably greater than an atmosphere and is in particular hour and then at one speed especially in the range from 10 to 50 atmospheres, with 0.000086 molar added per hour. The product the total pressure under which the process was carried out by vinyl acetate and the by-product acetaldehyde leads, suitably in the range from 1 to in the gas stream leaving the reaction solution

100 atmospheres. removed.

The gas mixture is preferably essentially The rate of reaction was as found

3 4

was, 4.1 mol / liter / hour, the reaction example 3
product

, _., "..". ■, ΐτ · in j Example 1, def

Γ ¹ ? ™ ¹⁸ " : ? ·} ^ X ^ Ä" ¹ ? Reaction conditions repeated:

Acetaldehyde 1.7 moles / liter / hour ₅ ^e

contained lithium acetate '.. 1. omolar

Lithium chloride 0.2 molar

Example 2 Copper (II) acetate 0.15 molar.

Example 1 was repeated using a gas mixtures io The temperature was 120 ⁰ C and the pressure

speed of 2200 liters per liter of reaction solution 25 atmospheres. The speed of the addition

repeated per hour The reaction rate of palladium (II) chloride was 1O ^-4 mol / liter /

was 2.4 mol / liter / hour, the reaction hour. The water content of the reaction solution was

product 11% (weight / weight) and the gas velocity

Vinyl acetate 1.26 Mo liter hour oxidation rate is 3.7 mol / liter /

Acetaldehy i 1.14 mole / liter / hour _s ^ _{walls (20 Mo} i _{/ Lit} e _{r /} hr of vinyl acetate and 1.7 mol /

contained. Liter / hour acetaldehyde).

Claims (1)

1 2 total olefin and oxygen, although small Claim: Inert compounds such as carbon dioxide are present Process for the preparation of unsaturated C ₂ - can be, especially in the case of a reaction to C ₄ acetic acid esters by reacting system with gas recirculation. The composition of ethylene, propylene or butylene with oxygen and S of the gas mixture can contain 1 to 40 percent by volume of acid-acetic acid in the presence of a redox system, the remainder being olefin, but a palladium salt and acetate ions and, in general, oxygen concentrations of 2 to optionally halide ions dissolved in the vinegar - 10% used, with the higher concentrated acid, at elevated temperature in the liquid phase, trations because of the combustible nature of the mixture, characterized in that caution is required. the mixture of olefin and oxygen in one The acetate ions can be in the reaction solution in Speed of at least 4000 liters / liter form of a metal salt, in particular an alkali, reaction solution / hour, preferably in the range of alkaline earth or copper acetate are introduced. ..— * nrv \ u; „ennn τ ; t _a ™ iT. ; * ",. p _M w; _nn ciÄo.m _O ; Ithium and sodium acetates are preferred. The Kon hour, initiates into the reaction solution. The concentration of the acetate ions is preferably u, z-dis 2.0 molar, with higher concentrations especially are beneficial in propylene oxidation. In this In this case, acetate ions can be used in concentrations up to 4.0 molar.